There have been scores of film adaptations of the works of Charles Dickens, but few movies have featured the great man himself. Still, he led a life as extraordinary as that of any of his characters.

“The Invisible Woman” is based on the 1990 Claire Tomalin biography detailing the long-term affair between Dickens (played by Ralph Fiennes, who also directed) and Nelly Ternan (Felicity Jones). It’s new enough in subject, if not in style, to serve as a welcome addition to the Dickens filmography.

Dickens met Nelly in 1857, when he was 45 and world famous and she was 18 and appearing in the Wilkie Collins play “The Frozen Deep” that Dickens was overseeing. The affair continued until the author’s death in 1870. Dickens’s wife, Catherine (Joanna Scanlan), the mother of his 10 children, knew full well of the affair, as did a swatch of Victorian society. Nelly’s widowed mother (played by Kristin Scott Thomas) actually encouraged the relationship.

Fiennes is temperamentally unsuited to playing a character of such high-decibel bluster; he’s more in his element playing snarly, poetic sufferers. But, of course, he is best known, at least to the mass audience, as Lord Voldemort in the “Harry Potter” movies. Certainly there was much bluster there (also a lot of CGI). His tirades and energy blasts in “The Invisible Woman” don’t quite fit him, but he doesn’t disgrace himself. His Dickens is a compromised hero – a great artist and performer who also truly cares about not only Nelly but also about his wife.

Written by Abi Morgan, the movie is even more about Nelly than it is about Dickens. (This is not “Dickens in Love.”) And because Jones gives such a searching and strong-willed performance, she makes Dickens’s love for Nelly, and hers for him, into something resembling passion.

Passion, however, is what is almost entirely missing from Fiennes’s direction. I didn’t particularly care for his directorial debut, “Coriolanus,” but it had a jagged energy that this film lacks. I understand that, as director, Fiennes was attempting to make an old-fashioned movie that wouldn’t gin up the Victoriana into high camp or low melodrama. But there are ways to be old-fashioned without being quite as fuddy-duddyish as much of “The Invisible Woman” – as in, for example, the best of the Merchant-Ivory movies.

There is at least one scene, though, in which all the best possibilities in this material come together. A train carrying the couple, with Dickens traveling under an assumed name, derails at high speed. In the ensuing disaster, Dickens is torn between being with Nelly and giving up his cover, or aiding the other victims at the behest of the police. It’s the kind of rich, jumbo-sized conflict that might easily have found its way into one of Dickens’s novels.

There is also a marvelous scene between Nelly and Dickens’s wife, who at first seems like no more than a rotund, long-suffering repository of Dickens’s philandering. We are quickly set straight. This woman has reserves of will, and compassion, even for Nelly, that make her formidable in her own right.“The Invisible Woman” at its best does justice to the complicatedness of its characters – just as Dickens did as a writer. Grade: B (Rated R for some sexual content.)